Slantfour Posted May 3, 2019 Report Share Posted May 3, 2019 After a pause of a few years I am now back to my TR6 rebuild and despite lots of pictures, there are aspects that I with! Does anyone have pictures of the exhaust fitted to the rolling chassis or from underneath a built up vehicle? My car is a CR series and the exhaust came from Bell's in Cricklade together with a fitting kit from Rimmer Bros. So far the rubber support straps do not facilitate the rear box sitting level, which I recon must be wrong! Thank you Quote Link to post Share on other sites
SeanF Posted May 4, 2019 Report Share Posted May 4, 2019 Hi There, (do you have a name?) I have these. Hope they help. Sean Quote Link to post Share on other sites
Waldi Posted May 4, 2019 Report Share Posted May 4, 2019 My rear box was not horizontal either, I had a fitting kit from Moss, but used Mikalor clamps. This combination did not go well for the RHS of the box. When I ordered an additional pair of standard clamps that i put besides the Mikalors for that position I got it level. Waldi Quote Link to post Share on other sites
astontr6 Posted May 4, 2019 Report Share Posted May 4, 2019 13 minutes ago, Waldi said: My rear box was not horizontal either, I had a fitting kit from Moss, but used Mikalor clamps. This combination did not go well for the RHS of the box. When I ordered an additional pair of standard clamps that i put besides the Mikalors for that position I got it level. Waldi I had the same problem with the rear box but corrected it by using jack on the dropped side and used standard exhaust U clamps, has never moved since and is gas tight. I think that the use of S/S pipework makes this more lightly to happen as there is much more movement in the pipe joints and one has to get the overall pipe lengths setting exactly correct. I did also use exhaust joint pipe sealant. Bruce. Quote Link to post Share on other sites
Waldi Posted May 4, 2019 Report Share Posted May 4, 2019 Hi Bruce, yes, U clamps is what I meant. You make a good point about the SS systems: The SS exhaust has a 50% higher thermal expansion compared to a mild steel exhaust, and the front is the fixed point, so all movement is towards the rear. A rough indication of the amount of movement: 1) Average metal temperature (not gas): 270 degr. C, this is an estimate, it will be higher or lower, depending on driving conditions etc. 2) Length: 3 meters 3) Expansion coefficient for austenitic SS: 1.8 mm/m/100 degr.C This results in an expansion from 20-270C: (270-20) /100 x 1.8 x 3.5 =16 mm. Especially the rear rubber mountings should be installed with a cold offset (rear box more to the front) , so it is as close as possible to neutral when hot. Waldi Quote Link to post Share on other sites
Slantfour Posted May 4, 2019 Author Report Share Posted May 4, 2019 Thank you all for the info, I did not realise that the S/S exhaust would expend so much! Quote Link to post Share on other sites
Waldi Posted May 4, 2019 Report Share Posted May 4, 2019 14 minutes ago, Slantfour said: I did not realise that the S/S exhaust would expend so much! Yes, it does; mild steel will expand at a rate of 1.2 mm/m/100C, so around 2/3 of a SS exhaust. Waldi Quote Link to post Share on other sites
Mike C Posted May 4, 2019 Report Share Posted May 4, 2019 For what it's worth I used to cold set pipes 50%- with the support on zero movement halfway between hot and cold. My rationale on this was that damage to the supports was minimized by limiting the movement to 50% each way rather than, say, 100% in one direction. Don't know if linear expansion would be a problem with my exhaust, there are a lot of bends to take it up. Quote Link to post Share on other sites
Waldi Posted May 5, 2019 Report Share Posted May 5, 2019 8 hours ago, Mike C said: For what it's worth I used to cold set pipes 50%- with the support on zero movement halfway between hot and cold. My rationale on this was that damage to the supports was minimized by limiting the movement to 50% each way rather than, say, 100% in one direction. Don't know if linear expansion would be a problem with my exhaust, there are a lot of bends to take it up. Hi Mike, the 50/50 method can be a good approach, as sometimes we are limited by bracket positions etc. Regarding the elbows influencing movement: they do not influence the thermal movement between 2 points, but do create some (limited) flexibility. Regards, Waldi Quote Link to post Share on other sites
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